INSECTICIDES 329 



meal, he believes that it would prove to be a thoroughly practical 

 method of dealing with the fl}- nuisance in larger places. 



The burning of pure and fresh pyrethrum powder and also the 

 dropping of twenty to thirty drops of carbolic acid on a hot iron 

 plate or shovel have been recommended as means of ridding 

 rooms of flies. As the fumes do not always kill all the flies but 

 only stupefy a certain proportion, it is important that the tiies 

 should be swept up and burnt before they have an opportunity to 

 recover \ 



' In a paper on "Experiments with House-fly Baits and Poisons," read by 

 A. W. Morrill of Phoenix, Arizona, before the Amer. Ass. of Economic Ento- 

 mologists at Atlanta, Ga., U.S.A., on 2nd Jan., 1914, the author described the 

 results of tests of various chemical and fruit baits. He found that the attractive- 

 ness of formalin varied from day to day, that formalin with vinegar, and vinegar 

 alone, were excellent baits, and that potassium bichromate, which is sometimes 

 recommended, has little value as an insecticide. The discussion on this paper 

 elicited various experiences among which were : that the formalin bait is more 

 successful if water is absent from the room and that a mixture of sour milk and 

 foi'malin sometimes gives good results. 



